How you winterize a pool depends first on what kind of pool you have. Intex's manual for its Ultra XTR and Prism Frame pools says that in a cold winter these pools are not closed with a cover at all: they must be drained and stored. An in-ground pool is normally closed with water in it and only its equipment drained (our understanding of standard practice). This page starts with that choice, then gives the steps for each. The frame pool and sand filter steps come from the makers' manuals; the order of the in-ground steps is our routine.
The short version: for Intex Ultra XTR and Prism Frame pools, Intex says you must drain, take down and store the pool when temperatures drop below 41°F (5°C), because ice can cause sudden liner failure or pool collapse. In milder winters it can stay up with a winter preparation. For in-ground and other permanent pools: balance and clean the water, lower the level as your equipment requires, drain the filter and pump, protect the lines and put on the cover. If children can get to the pool, look for a safety cover that meets ASTM F1346, the US standard for safety covers.
First: which pool do you have?
| Pool type | Cold winters (below 41°F / 5°C) | Milder winters |
|---|---|---|
| Intex Ultra XTR and Prism Frame pools | Drain, take down and store indoors (Intex: "must") | May stay up, with Intex's 9-step winter preparation |
| In-ground and other permanent pools | Close the pool: water stays in, equipment is drained, lines are protected, cover on | Follow your pool builder's advice for your climate |
The 41°F line comes from the Intex owner's manual for its Ultra XTR and Prism Frame pools. Other above-ground pools (other Intex models, other brands, steel-wall and resin pools) follow their own manual: the threshold and the steps can differ, and some are closed with water in them like an in-ground pool.
Intex frame pools in a cold winter: drain and store
Intex's manual is direct about it: you must drain, disassemble and properly store the pool when the temperature drops below 41°F (5°C) to prevent ice damage. The draining steps from the same manual, shortened:
- Check local rules for where pool water may be drained.
- Check that the drain plug inside the pool is in place, then remove the cap of the drain valve on the outside wall.
- Attach a garden hose to the drain connector and lead the other end to a spot where the water can drain away safely, away from the house.
- Attach the connector to the drain valve. It pushes the inside plug open and the pool starts draining.
- When the water stops, lift the pool wall on the side opposite the drain to lead the last water out.
- Put the drain plug back on the inside and the cap on the outside.
- Take the pool down in the reverse order of setting it up.
- Dry everything completely. Air-dry the liner in the sun before folding; Intex suggests a little talcum powder against sticking and leftover moisture.
- Store the liner and parts in a dry place between 32°F and 104°F (0°C to 40°C). The original box works for storage.
The filter pump goes indoors too: clean and drain the pump, filter housing and hoses first (Intex gives this step in its winter preparation list below).
Intex frame pools in a milder winter: Intex's winter preparation
If temperatures where you live do not drop below 41°F and you leave the pool up, Intex's manual gives these steps:
- Clean the pool water thoroughly.
- Remove the skimmer and any accessories on the strainer connector; clean and dry them before storage.
- Plug the inlet and outlet fittings from the inside with the plugs provided (pools up to 16 ft), or close the plunger valves (17 ft and up).
- Remove the ladder and store it dry.
- Remove the hoses between the pump and filter and the pool.
- Add winter chemicals: Intex advises asking your local pool dealer which ones and how, because this varies a lot by region.
- Cover the pool. Intex points out that its pool cover is not a safety cover.
- Clean and drain the pump, filter housing and hoses. Remove and discard the old filter cartridge, and keep a spare for next season.
- Store the pump and filter parts indoors, dry, preferably between 32°F and 104°F.
In-ground and permanent pools: the closing steps
A permanent pool normally stays filled over winter. These are the six steps in the order we use (our routine; your pool builder's or equipment maker's instructions come first where they differ).
1. Balance the water
Close the pool with clean, balanced water. Test chlorine and pH first; the values the CDC recommends for home pools are in our weekly pool maintenance checklist. For winter chemicals, follow the product labels or ask a local pool dealer, as Intex also advises: what works depends on your region.
2. Clean the pool
Skim, brush and vacuum one last time. Leaves left in the pool sit there all winter.
3. Lower the water level
Many pools are closed with the water below the skimmer so it cannot freeze in the skimmer. How far depends on your skimmer, your cover and your climate, so follow their instructions (our advice).
4. Drain the equipment
Water left in a filter, pump or heater can freeze and damage it (our advice; Hayward, for example, excludes freeze damage from its filter warranty). For a Hayward Pro Series sand filter, the owner's manual gives three steps:
- Drain the tank completely by unscrewing the drain cap at the base of the tank, and leave the cap off during winter.
- Set the control valve pointer between two positions so the water can drain out of the valve.
- Drain and winterize the pump according to the pump's own instructions.
Other filters have their own steps; Intex's pool manual, for example, says to drain the pump and filter housing, remove and discard the old cartridge and keep a spare for next season. Check the manual of your exact filter, pump and heater.
5. Protect the lines
In freezing climates, the water in the underground plumbing needs protection too. How that is done depends on how your pool was built, so follow your pool builder's instructions or have a pool professional do it (our advice).
6. Cover the pool
A winter cover keeps leaves and dirt out. If children can get to the pool, choose a safety cover: the US standard for safety covers is ASTM F1346, which is meant to keep children under five out of the water when the cover is installed and used as the maker directs. The CPSC's pool barrier guidelines say power safety covers should conform to ASTM F1346. A regular winter cover is not automatically a safety cover: check the label.
As an Amazon Associate we earn from qualifying purchases: see pool winter covers on Amazon (check the label if you need an ASTM F1346 safety cover).
When you open the pool again
- Remove every winterization plug from the suction outlets before you run the pump. Hayward's manual warns that plugs left in the suction outlets increase the risk of suction entrapment.
- Put the filter's drain cap back and make sure it is secure (Hayward's manual), and refit the pump's drain plugs and set the valve back as their manuals describe (our routine).
- Clean, test and balance the water, then go back to your weekly routine.
- Note your clean filter pressure again after the first cleaning; see what high pool filter pressure means.
Common mistakes
- Leaving a frame pool up through a freezing winter. Intex warns that ice damage can mean sudden liner failure or pool collapse.
- Putting the filter drain cap back on for winter. Hayward says to leave it off.
- Forgetting the pump. It has its own drain steps in its own manual.
- Treating any cover as a safety cover. The US standard for safety covers is ASTM F1346; check the label.
- Starting the pump in spring with winter plugs still in place. Remove them first.
- Folding a wet liner. Intex says to dry it completely first.
Sources
Frame pool threshold, draining, storage and the winter preparation: Intex owner's manual, Ultra XTR Rectangular and Prism Frame pools (06/15/2021). Sand filter winterizing and the suction outlet warning: Hayward Pro Series top-mount sand filter owner's manual (IS270T, Rev. B). Safety covers: ASTM F1346-23 (scope: keeping children under five out of the water), ASTM subcommittee F15.28 and the CPSC Safety Barrier Guidelines for Residential Pools. The order of the in-ground steps and the points marked as our advice are our own routine; your pool builder's and equipment makers' instructions come first.
Frequently asked questions
When should I winterize my pool?
For Intex Ultra XTR and Prism Frame pools, the manual is clear: drain and store the pool when temperatures drop below 41°F (5°C). For in-ground pools, close the pool before the first freeze (our advice); your pool builder can tell you the right moment for your climate.
Can I leave an Intex pool up in winter?
According to Intex's Ultra XTR and Prism Frame manual, only if temperatures where you live do not drop below 41°F (5°C). Then Intex gives a 9-step winter preparation: clean the water, plug the fittings, remove the hoses and ladder, add winter chemicals, cover the pool and store the pump and filter indoors.
Do I drain an in-ground pool for winter?
No, in-ground pools are normally closed with water in them; only the equipment is drained and the water level lowered as your skimmer and cover require (our understanding of standard practice). Ask your pool builder before draining one completely.
Should I leave the filter drain cap off?
For the Hayward Pro Series sand filter, yes: the manual says to leave the drain cap off during winter. Check the manual of your own filter.
Is a winter cover a safety cover?
Not automatically. The US standard for safety covers is ASTM F1346; Intex also notes that its own pool cover is not a safety cover. Check the label.
